Fluorinated hydrocarbons, detergents, deterging method, polymer-containing fluids, and method of forming polymer films

ABSTRACT

Providing a fluorinated hydrocarbon with excellent cleaning action, incombustibility and high stability in alkali or water and heat; and a polymer-containing solution prepared by dissolving or dispersing a polymer with film-forming potency, preferably a fluoropolymer, in a solvent containing trihydrofluorocarbon. More specifically, a fluorinated hydrocarbon containing trihydrofluorocarbon with 4 to 6 carbon atoms at 95% or more, as represented by the following formula, is provided, together with a polymer-containing solution containing the same: 
     
       
         Rf 1 —R 1 —Rf 2    (I)  
       
     
     wherein R 1  represents a carbon chain of CHF and CH 2 , bound to each other; Rf 1  and Rf 2  independently represent a perfluoroalkyl group; and Rf 1  and Rf 2  may be bound to each other, to form a ring.

This application is a 371 application of PCT/JP98/02158 filed May 15,1998.

TECHNICAL FIELD

The invention of the present application relates to a fluorinatedhydrocarbon, and a cleaning agent and a cleaning method. Additionally,the invention of the application relates to a polymer-containingsolution comprising a homogeneously dissolved or dispersed polymer, anda method for forming a polymer film on solid surface by using suchsolution. More specifically, the invention of the application relates toa fluorinated hydrocarbon comprising trihydrofluorocarbon, a solventcomposition useful for cleaning, water draining and drying articles andfor dissolving and dispersing a polymer with lubricating properties andthe like, and a cleaning agent containing the same as the effectiveingredient, a cleaning method for efficiently cleaning off stains fromarticles such as metal materials, plastic materials, glass materials andceramic materials, and a polymer-containing solution comprising ahomogeneously dissolved or dispersed polymer imparting lubricatingproperties and the like to solid surface, and a method for forming apolymer film on solid surface by using such solution.

BACKGROUND OF THE INVENTION

As industrial cleaning methods of various materials, conventionally, usehas been made in a wide variety of fields of solvent compositionscontaining CFC113 and 1,1,1,-trichloroethane with excellentincombustibility, low toxicity and good stability as the principalcomponents. However, it has been remarked that various types of CFC,1,1,1,-trichloroethane, and carbon tetrachloride and the like damage theozone layer, leading to the absolute worldwide banning of the productionof CFC113, 1,1,1-trichloroethane and the like since the end of 1995 andto the use thereof under regulation, from the standpoint of theprotection of the ozone layer.

As alternatives of these CFC113 and the like, hydrochlorofluorocarbonssuch as HCFC225 and HCFC141b have been proposed and used practically.But a time limit is imposed to the use thereof because these have alsodamaging potencies of the ozone layer although the potencies areextremely low. Furthermore, conventional chlorine containing solventsincluding for example methylene chloride, trichloroethylene, andperchloroethylene are so problematic in terms of safety profile(oncogenesis and intoxication) that these have been also under variousregulations or have been under way of regulatory controls.

Still furthermore, various compounds have been proposed, which canretain the advantages of these fluorine containing solvents, such asincombustibility and stability, but never contain chlorine atom as theessential factor for the ozone layer depletion. The compounds includefor example those principally comprising perfluorocarbons such asperfluoro-n-heptane (WO 92-03205, etc.), those principally comprisingacyclic hydrofluorocarbons (WO 95-06693, JP-W-6-501949) and thoseprincipally comprising specific cyclic hydrofluorocarbons (WO 95-05448).

For the purpose of endowing solid surface with lubricating properties,non-coherent properties, water-repelling properties, conventionally, amethod has been used for forming a polymer film with lubricatingproperties, non-coherent properties, and water-repelling properties onsolid surface by using a solution dissolving or dispersing a polymertherein.

As electronic devices, machines and appliances and parts have beendown-sized and highly sophisticated, these are required to have highlubricating properties at the sliding parts and surfaces thereof.Lubricating properties and non-coherent properties at high precision,high durability and high reliability have been demanded specifically forsliding between hard disk, mini-disc, magnetic tapes such as digitalaudio tape or video tape, other magnetic record media or optical disksand record/read-out heads. For sliding between hard disk andrecord/read-out head, for example, a protective layer of carbon and thelike is formed on a magnetic layer; and then, a polymer film comprisinga lubricating fluoro polymer is additionally formed thereon. Because thesliding parts of machines and appliances such as cameras, video cameras,office machines, medical apparatuses, vacuum machines such as vacuumpumps, electronic parts, precision automobile parts, small motor,ultrasonic motor and micro-machine should be endowed with lubricatingproperties with high durability, high reliability and low stainingproperties, due to the demands for high performance and down-sizingthereof, polymer films comprising lubricating fluorine-series polymersare likely to be formed on the sliding parts of these machines andappliances. So as to securely impart discharge stability and orientationto polar liquids, polymer films comprising water-repellent fluorinatedpolymers are formed on the nozzle surface on the nozzle opening ofinkjet recording head.

Conventionally, various propositions have been made regarding the methodfor forming polymer films on such solid surfaces. For example, a methodcomprises dissolving a polymer with a small surface tension, such asfluoro polymer with lubricating properties or water repellency, in anappropriate volatile solvent, coating the resulting solution on variousmaterials or parts, and thereafter vaporizing the solvent to form apolymer film.

A solution prepared by dissolving a fluoro polymer in a fluorinatedsolvent has been known. CFC 113 (JP-A-5-342570) and perfluoro-n-heptane(JP-A-4-211959) are reported as such fluorinated solvents. However, theproduction and marketing of conventional CFC 113 is prohibited under theregulation against ozone layer layer-depletion substances, whileperfluorocarbons such as perfluoro-n-heptane are disadvantageous becauseof the poor solubility so that a uniform fluorinated polymer film cannotbe recovered.

JP-A-3-158884 describes a process of coating a dispersion prepared bydispersing polyvinylidene fluoride, a phenolic resin or tospearl inparticles in a liquid medium selected from isopropyl alcohol, ethylalcohol, CFC 113 and water on the contact part between the image carrierin an imaging apparatus and a member material in contact to the imagecarrier, and subsequently drying the dispersion. It is described thataccording to the process, the friction between the image carrier and acleaning blade in contact to the carrier can be reduced, leading to theresolution of problems including blade peel off or non-uniformly chargedstate of the surface of the image carrier.

JP-A-3-197952 describes a process of spraying a dispersion of particlessuch as fluorine resin particles or silicone resin particles in anorganic solvent on the surface of an electrophotographic photosensitivematerial and then drying the dispersion. The organic solvent includingCFCs is exemplified. It is described that according to the process, thefriction between the photosensitive material and the cleaning blade forremoving residual toner is reduced, whereby the problem of blade peeloff can be overcome.

Because these polymers with lubricating properties are not homogeneouslydispersed or dissolved in the polymer-containing solutions, polymerfilms prepared by coating the polymer-containing solutions on solidsurface and removing the liquid medium are not uniform on the solidsurface. Hence, the effect of the polymer films to reduce friction onthe solid surface cannot be exerted sufficiently.

As has been described above in detail, the perfluorocarbons andhydrofluorocarbons are preferable in terms of no concern of the ozonelayer depletion, and good cleaning performance with great finish, whenused as they are or in combination with organic solvents. Nevertheless,they individually have problems to be overcome. For example,perfluorocarbons have high global warming potentials, leading to thepossible occurrence of new problems from the standpoint of theprotection of global environment. Additionally, cyclic or acyclichydrofluorocarbons of various structures have been proposed, but theyare problematic, structurally. For example, hydrofluorocarbons of astructure with a —CF₂CHFCHFCF₂— bond are disadvantageous in terms ofpoor stability in the presence of basic compounds or water.

It is the object of the first aspect of the invention of the applicationto provide a fluorinated hydrocarbon with excellent cleaningperformance, great incombustibility and high stability in the presenceof water, which can overcome the drawbacks of such conventionally knownhydrofluorocarbons and can be produced readily, a method for producingthe same and a solvent composition thereof, and a cleaning agent and acleaning method, using the same.

It is the object of the second aspect of the invention of theapplication, to provide a polymer-containing solution and the likecapable of forming a uniform polymer film on solid surface bysufficiently enhancing the homogenous dissolution of a polymer in thepolymer-containing solution, and a process of forming a polymer filmusing the same, because a polymer-containing solution capable of forminga uniform polymer film on solid surface has been desired althoughconventional techniques for forming polymer film as described above canexert only a limited effect on the improvement of solid surface.

DISCLOSURE OF THE INVENTION

So as to overcome the problems, in accordance with the invention of theapplication, it is provided a fluorinated hydrocarbon containing cyclictrihydrofluorocarbon with 5 carbon atoms and a purity of 95% by weightor more, as represented by the following formula(I):

Rf₁—R₁—Rf₂  (I)

wherein R₁ represents a carbon chain of CHF and CH₂, bound to eachother; Rf₁ and Rf₂ are bound to each other to form a ring of aperfluoroalkylene chain.

In accordance with the invention of the application, a method forproducing the fluorinated hydrocarbon, comprising subjectingdihydrofluorocarbon represented by the following formula II to an alkalitreatment and hydrogenating the resulting product is provided:

Rf₁—CHF—CHF—Rf₂   (II)

wherein Rf₁ and Rf₂ independently represent a perfluoroalkyl group andRf₁ and Rf₂ may be bound to each other, to form a ring. Additionally,the invention of the application provides a cleaning agent containingthe fluorinated hydrocarbon or a solvent composition thereof as theeffective ingredient, a method for cleaning articles, comprising a stepof removing staining substances deposited on articles by putting thearticles in contact to an organic solvent comprising at least oneselected from hydrocarbons, alcohols, esters, chlorinated hydrocarbons,fluorinated hydrocarbons, ethers, ketones, and volatile organicsilicones, and a step of rinse cleaning the articles, comprising puttingthe organic solvent deposited on the articles after the removal of thestaining substances in contact to the cleaning agent, thereby rinsecleaning the articles, or comprising a step of vapor cleaning thearticles in the vapor of the cleaning agent.

Additionally, the invention of the application provides apolymer-containing solution prepared by dissolving or dispersing apolymer with film-forming potency in an organic solvent containing thefluorinated hydrocarbon or a solvent composition thereof. Furthermore,the invention of the application provides a method for forming a polymerfilm on solid surface, comprising coating the polymer-containingsolution on the solid surface and removing the liquid medium.

BRIEF DESCRIPTION OF THE DRAWINGS

The FIGURE is a composition figure depicting one example of theapparatus for rinsing and cleaning in accordance with the application,wherein the symbols represent those described below:

1. cleaning vessel 1

2. cleaning vessel 2

3. rinse cleaning vessel

4. separator

5. vapor cleaning vessel

6. cleaning agent layer

7. trihydrocarbon layer

8. vapor zone

9. heating apparatus

10. ultrasonic oscillation apparatus

11. circulation pump

12. circulation pump

13. cooling coil

14. rinse solution transfer pump

15. destillation column

BEST MODE FOR CARRYING OUT THE INVENTION

As described above, the fluorinated hydrocarbon of the inventioncharacteristically comprises a cyclic trihydrofluorocarbon with 5 carbonatoms and a purity of 95% by weight or more, wherein 3 hydrogen atomsbind onto two adjacent carbon atoms. The inventive fluorinatedhydrocarbon comprising such cyclic trihydrofluorocarbon at a high purityof 95% by weight or more has never been known so far or has never beenprovided in a practical sense, although the flourinated hydrocarboncontains an extremely small amount of other fluorocarbons. This is dueto the facts that any specific production method thereof has never beenestablished and that the excellent characteristic properties of thecyclic trihydrofluorocarbon or any applicability thereof to cleaning orlubrication has never been known.

The number of carbon atoms in the trihydrofluorocarbon of this inventionrepresented by the formula I is 5, is preferably at a boiling point of25° C. or more to 150° C. or less, particularly preferably at a boilingpoint of 50° C. or more to 100° C. or less. Such fluorinated hydrocarbonis cyclic.

The inventive fluorinated hydrocarbon comprising this cyclictrihydrofluorocarbon at a high purity is inflammable, highly stable inthe presence of basic compounds and water and applicable as a cleaningagent of material surface, due to the characteristic properties ofcyclic trihydrofluorocarbons and is thus useful as a liquid medium forforming a lubricating polymer film capable of significantly reducingfriction on solid surface.

In accordance with the invention, the cyclic trihydrofluorocarbonrepresented by the formula I is contained at a high content of 95% byweight or more. Possibly, other contaminating fluorocarbons includesaturated or unsaturated perfluorocarbons and hydrofluorocarbons beinginevitably contained therein at the production process and having thesame number of carbon atoms.

As described above, the invention also provides a method of producing afluorinated hydrocarbon which comprises subjecting dihydrofluorocarbonrepresented by the formula II to an alkali treatment and subsequentlyhydrogenating the resulting product. For the alkali treatment of themethod, any treatment agent at alkalinity may be used with no specificlimitation and includes for example metal hydrogen carbonate salts suchas sodium hydrogen carbonate and potassium hydrogen carbonate; metalcarbonate salts such as lithium carbonate, sodium carbonate, potassiumcarbonate, calcium carbonate, magnesium carbonate and barium carbonate;hydroxides such as lithium hydroxide, sodium hydroxide, potassiumhydroxide, calcium hydroxide, magnesium hydroxide and barium hydroxide;anion exchange resins; ammonia and amines such as triethylamine andmorpholine; and alkali metal compounds such as metal alkoxides andGrignard's reagent. Among them, preference is given to metal hydrogencarbonate salts and metal carbonate salts.

As to the amount of an alkali to be used, the alkali is used at anequivalent amount or more to one mole of the dihydrofluorocarbon. Anyreaction temperature is satisfactory, with no specific limitation, butgenerally, the reaction temperature is about 0 to 100° C., preferablyabout 10 to 80° C. For the alkali treatment, furthermore, a reactionadditive may satisfactorily be added. The additive is preferably anphase transfer catalyst. Any phase transfer catalyst is satisfactory,with no specific limitation, as long as the catalyst is generally usedfor synthetic reaction; the phase transfer catalyst includes for examplequaternary salts such as quaternary ammonium halides and quaternaryphosphonium halides; polyethers such as crown ethers and polyoxyalkyleneglycols; and aminoalcohols. Quaternary salts are particularlypreferable.

The quaternary salts comprise a cation (positive ion) prepared bybinding four substituents containing carbon atom to a hetero atom suchas nitrogen atom and phosphorus atom, and a pair anion (negative ion).

These phase transfer catalysts may be used singly or in combination withtwo or more thereof.

The alkali treatment in accordance with the invention may be carried outin two layers of water and the dihydrofluorocarbon, satisfactorily, buta part or the entirety thereof may be substituted with a polar solvent.The polar solvent includes for example alcohols such as methanol,ethanol and isopropanol; glycols such as ethylene glycol; glycol etherssuch as ethylene glycol monomethyl ether; sulfoxides such as dimethylsulfoxide; sulfolanes; amides such as dimethylformamide,dimethylacetamide and N-methylpyrrolidone; and ureas such asdimethylimidazolidinone.

Furthermore, the subsequent hydrogenation is preferably carried out byusing for example noble metal catalysts and the like at atmosphericpressure to a pressure of about 10 kgf/cm² and a reaction temperature ofambient temperature to about 350° C., with no specific limitation alike.Still further, liquid phase reaction or gas phase reaction may beselected appropriately for the reaction.

As the noble metal catalysts, generally, use is made of a noble metalimmobilized on a carrier. The noble metal herein referred to includespalladium, rhodium, ruthenium, rhenium or platinum, and is preferablypalladium, rhodium or ruthenium. These raw metals may be used singly orin the form of an alloy in combination with two or more thereof, namelyso-called bimetal catalyst. The type, shape and size of the carrier arenot specifically limited, but preferably, the carrier is activecharcoal, alumina or titanium, in powder or in a molded article insphere or pellet.

The amount of the noble metal immobilized on the carrier is generally0.5 to 20% by weight, but preferably, it is recommended that the amountthereof is 1 to 20% by weight, provided that the carrier is powdery orthat the amount is 1 to 10% by weight, provided that the carrier is amolded article. More preferably, a powdery catalyst at an immobilizationamount of 1 to 10% by weight is recommended, whereby a fluorinatedhydrocarbon at a cyclic trihydrofluorocarbon content of 95% by weightcan be produced.

The raw material dihydrofluorocarbon represented by the formula II canreadily be prepared by hydrogenation and the like of the correspondingperfluoroolefin (cycloolefin).

The inventive fluorinated hydrocarbon substantially comprising cyclictrihydrofluorocarbon or containing the same as the principal componentis obtained as one kind of product of the production method as describedabove, but may compose a solvent composition substantially containingcyclic trihydrofluorocarbon alone but inevitably containing negligiblebyproducts or impurities inevitably produced at the production processor preparation process of the composition or containing the cyclictrihydrofluorocarbon as the principal component.

The composition of the fluorinated hydrocarbon comprising cyclictrihydrofluorocarbon or containing the same as the principal componentwith a solvent is useful as a cleaning agent or for preparingpolymer-containing solutions and the like. For these applications, thecomposition effectively contains at least one organic solvent at aboiling point of 25° C. or more to 250° C. or less. Such organic solventis added at any amount, with no specific limitation, but generally, theamount is at 50% by weight or less, preferably 2 to 30% by weight andmore preferably 3 to 20% by weight to the total weight. When thetrihydrofluorocarbon or the fluorinated hydrocarbon containing the sameas the principal component and such organic solvent together are allowedto form an azeotropic composition, these are used at amounts forpreparing an azeotropic composition.

Along with hydrocarbons, alcohols, esters, halogenated hydrocarbons,ethers and ketones, the inventive fluorinated hydrocarbon comprisingcyclic trihydrofluorocarbon or containing the same as the principalcomponent forms an azeotropic composition.

When the inventive cyclic trihydrofluorocarbon is1,1,2,2,3,3,4-heptafluorocyclopentane, for example, an azeotropiccomposition is formed together with hydrocarbons such as n-octane,2,2,4-trimethylpentane, and n-heptane; alcohols such as methanol,ethanol, isopropanol, 1-butanol and 2-butanol; chlorinated hydrocarbonssuch as trichloroethylene and tetrachloroethylene; and other fluorinatedhydrocarbons such as ethyl perfluorobutyl ether and perfluorooctane.

More specifically, the azeotropic temperature of the azeotropiccomposition of 1,1,2,2,3,3,4-heptafluorocyclopentane and n-octane is 79°C., wherein the composition ratio of n-octane is 7.8% by weight. Theazeotropic temperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and 2,2,4-trimethylpentane is 75°C., wherein the composition ratio of 2,2,4-trimethylpentane is 21.2% byweight. The azeotropic temperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and n-heptane is 73° C., whereinthe composition ratio of n-heptane is 12.8% by weight. The azeotropictemperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and methanol is 60° C., whereinthe composition ratio of methanol is 23.1% by weight. The azeotropictemperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and ethanol is 69° C., wherein thecomposition ratio of ethanol is 18.4% by weight. The azeotropictemperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and isopropanol is 73° C., whereinthe composition ratio of isopropanol is 19.6% by weight. The azeotropictemperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and 1-butanol is 80° C., whereinthe composition ratio of 1-butanol is 2.3% by weight. The azeotropictemperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and 2-butanol is 79° C., whereinthe composition ratio of 2-butanol is 8.4% by weight. The azeotropictemperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and trichloroethylene is 73° C.,wherein the composition ratio of trichloroethylene is 21.3% by weight.The azeotropic temperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and tetrachloroethylene is 79° C.,wherein the composition ratio of tetrachloroethylene is 7.3% by weight.The azeotropic temperature of the azeotropic composition of1,1,2,2,3,3,4-heptafluorocyclopentane and trans-1,2-dichloroethylene is46° C., wherein the composition ratio of trans-1,2,-dichloroethylene is84% by weight. The azeotropic temperature of the azeotropic compositionof 1,1,2,2,3,3,4-heptafluorocyclopentane and ethyl perfluorobutyl etheris 74° C., wherein the composition ratio of ethyl perfluorobutyl etheris 75.3% by weight. The azeotropic temperature of the azeotropiccomposition of 1,1,2,2,3,3,4-heptafluorocyclopentane and perfluorooctaneis 78° C., wherein the composition ratio of perfluorooctane is 34.2% byweight.

For the application to a cleaning agent in another aspect of theinvention, the fluorinated hydrocarbon comprising cyclictrihydrofluorocarbon or containing the same as the principal componentcan be used in a composition with hydrocarbons, alcohols, esters,chlorinated hydrocarbons, brominated hydrocarbons, other fluorinatedhydrocarbons, ethers, and ketones. Preferably, the fluorinatedhydrocarbon comprising cyclic trihydrofluorocarbon or containing thesame as the principal component can be used in an azeotropic compositionwith hydrocarbons, alcohols, esters, chlorinated hydrocarbons, otherfluorinated hydrocarbons, ethers, and ketones. More preferably, thefluorinated hydrocarbon comprising cyclic trihydrofluorocarbon orcontaining the same as the principal component can be used in aazeotropic composition with alcohols or hydrocarbons or chlorinatedhydrocarbons or other fluorinated hydrocarbons. Most preferably,1,1,2,2,3,3,4-heptafluorocyclopentane can be used in an azeotropiccomposition with 1-butanol, 2-butanol, n-octane, 2,2,4-trimethylpentane,n-heptane, trichloroethylene, tetrachloroethylene, ethyl perfluorobutylether, and perfluorooctane.

The inventive fluorinated hydrocarbon or cyclic trihydrofluorocarbon anda solvent composition comprising the same are most characteristicallyapplied as a cleaning agent or a polymer-containing solution; forexample, the cleaning agent characteristically contains the inventivefluorinated hydrocarbon or cyclic trihydrofluorocarbon as the effectiveingredient.

Any type of organic solvents may be used for preparing solventcompositions, with no specific limitation, and includes at least oneorganic solvent selected from for example hydrocarbons, alcohols,esters, chlorinated hydrocarbons, other fluorinated hydrocarbons,ethers, ketones, and volatile organic silicones.

With no specific limitation, the hydrocarbons include for examplealiphatic hydrocarbons such as n-pentane, n-hexane, n-heptane,isohexane, isoheptane, n-octane, isooctane, n-decane, isodecane,n-undecane, n-dodecane, and n-tridecane; alicyclic hydrocarbons such ascyclopentane, methylcyclopentane, cyclohexane, and methylcyclohexane;and aromatic hydrocarbons such as benzene, toluene and xylene.

With no specific limitation, the alcohols include for example methanol,ethanol, isopropanol, n-propanol, n-butanol, s-butanol, t-butanol,n-pentanol, isopentanol, n-hexanol, isohexanol, 2-ethylhexanol andn-octanol. Among them, preference is given to alcohols with 5 or lesscarbon atoms; and furthermore, alcohols with 1 to 4 carbon atoms arespecifically preferable.

With no specific limitation, the esters include for example methylacetate, ethyl acetate, propyl acetate, isopropyl acetate, butylacetate, isobutyl acetate, pentyl acetate, methylpropionic acid,ethylpropionic acid, propylpropionic acid, isopropylpropionic acid,methylbutylic acid, ethylbutylic acid, isopropylbutylic acid,methylvaleric acid and ethylvaleric acid. Among them, preference isgiven to esters with 3 to 10 carbon atoms, particularly esters with 3 to6 carbon atoms.

With no specific limitation, the chlorinated hydrocarbons include forexample methylene chloride, dichloroethane, dichloroethylene,trichloroethylene and perchloroethylene.

With no specific limitation, other fluorinated hydrocarbons mayprincipally be composed of carbon, hydrogen and fluorine and maysatisfactorily contain oxygen atom or unsaturated bonds. Among them,fluorinated hydrocarbons at a boiling point of 25° C. or more arepreferable and include for example pentafluoropropane, hexafluorobutane,decafluoropentane, hexafluorocyclopentane, octafluorocyclopentane,perfluoropropyl methyl ether, perfluorobutyl methyl ether,perfluorobutyl ethyl ether, hexafluorocyclopentene,heptafluorocyclopentene and octafluorocyclopentene. Furthermore,preference is given to hexafluorocyclopentane, octafluorocyclopentaneand hexafluorocyclopentene, because of the cyclic structures and theappropriate boiling points.

With no specific limitation, the ketones include for example acetone,2-butanone, 2-pentanone, 3-pentanone, 2-hexanone, 3-methyl-2-butanone,cyclopentanone, cyclohexanone, 2-methylcyclopentanone and2-methylcyclohexanone.

The volatile organic silicones include hexamethyldisiloxane,ocatamethyltrisiloxane, decamethyltetrasiloxane,hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, anddecamethylcyclopentasiloxane.

Still furthermore, conventionally known various additives can be addedto the inventive cleaning agent. The additives include for examplestabilizers and surfactants. With no specific limitation, thestabilizers specifically include aliphatic nitro compounds such asnitromethane and nitroethane; acetylene alcohols such as3-methyl-1-butyn-3-ol, and 3-methyl-1-pentyn-3-ol; epoxides such asglycidol, methyl glycidyl ether and acrylglycidyl ether; ethers such asdimethoxymethane and 1,4-dioxane; unsaturated hydrocarbons such ashexene, heptene, cyclopentene and cyclohexene; unsaturated alcohols suchas allyl alcohol and 1-buten-3-ol; and acrylate esters such as methylacrylate and ethyl acrylate.

As the surfactants, then, use can be made of known anion activators,cation activators, nonion activators and amphoteric activators. Theanion activators include for example carboxylate salts, sulfonate salts,sulfate ester salts, and phosphate ester salts. The cation activatorsinclude for example amine salts of various acids and quaternary ammoniumsalts. The nonionic activators include for example polyoxyethyleneether, polyoxyethylene-polyoxypropylene glycol,polyoxyethylene-polyoxypropylene alkyl ether, and esters of fatty acidmoieties of polyhydric alcohols. The amphoteric activators include forexample betaines, amino organic acids and amine salts of fatty acids.

Additionally, activators comprising these compounds containing fluorineatom in the molecules are preferable. When these surfactants are added,deposited water on processed parts comprising metals, ceramics, glass,and plastic elastomers can effectively be removed after water cleaning,so these parts can be dried.

With no specific limitation, the amount of these surfactants to be addedis generally at 30% by weight or less, preferably 20% by weight or lessand more preferably 0.005 to 10% by weight to the total weight.

With no specific limitation, the cleaning subject materials inaccordance with the invention include for example processed partscomprising metal, ceramics, glass, plastic and elastomers in precisionmachine industries, metal processing industries, optical deviceindustries, electronics, and plastic industries. More specifically, awide variety of examples are illustrated, including automobile partssuch as bumper, gear, mission parts and radiator parts; electronic andelectric devices such as printed circuit boards, IC parts, lead frames,motor parts and condensers; precision machine parts such as bearings,gears, empra gears, clock parts, camera parts and optical lens;printers, printer blades, print rolls, press products, buildingmachines, glass substrates, parts of large machines such as largeheavy-duty machines, daily products such as dishes, and fiber products.

The staining substances include various types, for example oils such ascutting oil, hardening oil, press oil, lubrication oil, machine oil,press processing oil, punching oil, drawing oil, fabrication oil andlining oil; greases, waxes, adhesives, fatly acid esters, release agentsfor molding, finger mark; and fluxes, resists, and solder pastes aftersoldering.

The cleaning method satisfactorily comprises putting a cleaning subjectmaterial in contact to the cleaning solvent composition. Generalcleaning methods are applicable. More specifically, for example, methodsby hand wiping, immersion, spraying and shower are applicable. For thesetreatments, if necessary, physical means such as ultrasonic vibration,shaking, agitation and brushing may be used in combination.

For cleaning, an organic solvent comprising at least one selected fromaliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons,alcohols, esters, chlorinated hydrocarbon, ethers, ketones and volatileorganic silicones can be used satisfactorily as another solventdifferent from the cleaning agent in accordance with the invention.

In this case, a method comprising two steps, namely a step of removingstaining substances from a cleaning subject material and a step ofcleaning and rinsing off the organic solvents deposited on the materialafter removal of the staining substances by putting the material incontact to the inventive solvent or by vapor cleaning the material inthe vapor of the cleaning agent, is selectively used and includes forexample the following cleaning method (so-called co-solvent system).

Co-solvent system

(1) Cleaning step

At the first step, a cleaning subject material is cleaned in a cleaningagent comprising as the principal component at least one organic solventselected from hydrocarbons, alcohols, ethers, ketones and volatileorganic silicones.

The hydrocarbons include for example aliphatic hydrocarbons and aromatichydrocarbons, which are saturated acyclic, unsaturated acyclic,saturated cyclic or unsaturated cyclic; among them, aliphatichydrocarbons are preferable; and particularly preferable are aliphatichydrocarbons, saturated acyclic and unsaturated cyclic. The number ofcarbon atoms in these hydrocarbons may appropriately be selected,depending on the cleaning use (purpose). Generally, the number is 5 to30, preferably 8 to 20 and more preferably 10 to 15.

These hydrocarbons include for example saturated acyclic aliphatichydrocarbons, such as pentane, hexane, heptane, octane, isooctane,nonane, decane, isodecane, undecane, dodecane, isododecane, tridecane,tetradecane, pentadecane, hexadecane, heptadecane, octadecane andisooctadecane; saturated cyclic hydrocarbons such as cyclopentane,methylcyclopentane, cyclohexane, methylcyclohexane, cyclodecane,methylcyclodecane, cyclododecane, decalin, and norbornane; unsaturatedhydrocarbons in chain, such as heptene, heptadiene, octene, octadiene,nonene, nonadiene, decene, decadiene, undecene, dodecane, dodecadiene,tridecene, tridecadiene, tetradecene, tetradecadiene, octadecene,octadecadiene, and isoprene dimer; cyclic unsaturated hydrocarbonsincluding terpenes, such as α-pinene, β-pinene, γ-terpinene, δ-3-carene,limonene, and dipentene; and aromatic hydrocarbons such as toluene.Among them, preference is given to decane, undecane, dodecane,tridecane, tetradecane, pentadecane, limonene, and dipentene. Thesehydrocarbons can be used singly or in combination with two or morethereof. As commercially available hydrocarbon cleaning solvents, usecan be made of Normal Paraffin series, Isozol series, and Isolan series(manufactured by Nippon Petroleum Co., Ltd.), Solbents Nos. 0 to 5 andTeclean Series (Nippon Petroleum Co., Ltd.), NS Clean Series(manufactured by Nikko Petroleum Chemical Industries, Co. Ltd.) and thelike.

Cleaning solvents containing these hydrocarbons as the principalingredients can be used. The solvents contain only hydrocarbons orcontain various additives in addition to the base hydrocarbons, likecutting oil, lubrication oil, machine oil and press processing oil.

The alcohols include for example alcohols where at least one hydroxylgroup is bound to a hydrocarbon residue, saturated acyclic, unsaturatedacyclic, saturated cyclic or unsaturated cyclic. These hydrocarbonresidues may contain a functional group such as alkoxyl group. Thenumber of carbon atoms in the hydrocarbon residue is appropriatelyselected, depending on the purpose of cleaning, and generally, thenumber is 1 to 15, preferably 4 to 10. Such alcohols include methanol,ethanol, propanol, isopropanol, isopropanol, butanol, hexanol,1-hexenol, 2-ethylhexanol, cyclopentanol, cyclohexanol, decyl alcohol,ethylene glycol, 1,2-propane diol, 1,2-cyclopentane diol, ethyleneglycol monomethyl ether, and ethylene glycol monobutyl ether.

The ethers include for example ethers where at least one alkoxyl groupis bound to a hydrocarbon residue, saturated acyclic, unsaturatedacyclic, saturated cyclic and unsaturated cyclic; additionally, theethers include ethers where oxygen and a carbon chain together maysatisfactorily form a cyclic structure. The number of carbon atoms isappropriately selected, depending on the purpose of cleaning; and thenumber is generally 4 to 15, preferably 4 to 10. Such ethers includediethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran,1,3-dioxane, trioxane, cyclopentyl methyl ether, cyclohexyl ethyl ether,ethylene glycol dimethyl ether, ethylene glycol diethyl ether, anddiethylene glycol dimethyl ether.

As the volatile organic silicon, additionally, use is made of a volatileorganic silicone substantially comprising at least one low molecularpolyorganosiloxane selected from linear or cyclic polydiorganosiloxanerepresented by the following formulas 1 and 2:

wherein R may be the same or different and represent a monovalentorganic group, substituted or unsubstituted; n represents an integer of0 to 3; and m represents an integer of 3 to 5.

The R in the formulas includes for example alkyl groups such as methylgroup, ethyl group, propyl group and butyl group; aryl groups such asphenyl group; substituted alkyl groups such as trifluoromethyl group andpentafluoroethyl group; lower alkoxyl groups such as methoxy group andethoxy group; carbonyl-containing groups such as methyoxycarbonyl group,ethoxycarbonyl group and acetyl group; and amide group. From the respectof compound stability, preference is given to methyl group, ethyl group,methoxy group and ethoxy group. Methyl group is the most preferable.

As to n and m in number in the formulas, preferably, n is 0 or more andm is 3 or more, from the respects of formation of silicone structure andof cyclic stability for cyclic polydiorganosiloxane. Preferably, n is 3or less and m is 5 or less, whereby the resulting cleaning agent can besubjected to distillation in a practical sense for recycling.

Such silicon containing cleaning agent includes for example,hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane,hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, anddecamethylcyclopentasiloxane. Among them, preference is given tooctamethylcyclotetrasiloxane, in particular, from the respect ofphysico-chemical properties such as boiling point and surface tension.If necessary, surfactants and water can be added to these cleaningagents.

Furthermore, the cleaning agent can be used in repetition, afterdistillation and recovery. In this case, cleaning solutions describedbelow may partially be contained in the resulting recovered product,with no problem.

The cleaning method satisfactorily comprises putting a cleaning subjectmaterial in contact to the cleaning solvent, according to generalcleaning processes. Specifically, the cleaning processes include handwiping, immersion, spraying, and shower; immersion process isparticularly preferably used. For immersion treatment, physical meanssuch as ultrasonic vibration, shaking, agitation, and brushing can beused in combination. The temperature of the cleaning solvent mayappropriately be selected, depending on the properties of the cleaningsubject material. Generally, the temperature is within a range ofambient temperature to the boiling point thereof, preferably 40° C. ormore to the boiling point, and more preferably 50° C. or more to theboiling point.

(2) Rinse cleaning process

After the above cleaning process, the cleaning subject material, onwhich the cleaning solvent is deposited, is then rinse cleaned by usinga cleaning agent containing the inventive fluorinated hydrocarboncomprising cyclic trihydrofluorocarbon at a high purity of containingcyclic trihydrofluorocarbon per se, as the principal ingredient.

By using the inventive high-purity cyclic trihydrofluorocarbon as therinse cleaning solvent, the rinse cleaning power of hydrocarbon can beprominently improved, compared with acyclic hydrofluorocarbon orperfluorocarbon. The difference in the effect can be distinctivelyexerted when cleaning subject materials are continuously cleaned.

The inventive cyclic trihydrofluorocarbon can be used singly or incombination with two or more types thereof.

The rinse cleaning agent containing the fluorinated hydrocarbon orcyclic trihydrofluorocarbon as the principal ingredient is used inaccordance with the invention, as described above, but a single type ofcyclic trihydrofluorocarbon (a single type of cyclictrihydrofluorocarbon or a mixture of two or more types of cyclictrihydrofluorocarbon) or a combination of cyclic trihydrofluorocarbonwith another organic solvent can be used. Another organic solventincludes those generally used as rinse cleaning solvents, for examplelinear saturated hydrocarbons such as hexane, octane and isooctane;cyclic saturated hydrocarbons such as cyclopentane and cyclohexane;aromatic hydrocarbons such as toluene and xylene; lower alcohols such asmethyl alcohol, ethyl alcohol, propyl alcohol, and isopropyl alcohol;ketones such as acetone and methyl ethyl ketone; ethers such as dimethylether and diethyl ether; esters such as vinyl acetate; acyclichydrofluorocarbons, such as 1,1,1,2,2,3,4,5,5,5-decafluoropentane; andperfluorocarbons such as perfluorohexane and perfluoroheptane. Theseother organic solvents can be used singly or in combination of two ormore thereof; these are used at an amount appropriately selected withina range with no adverse effects on the effect of the invention;generally, the amount is 40% by weight or less, preferably 20% by weightor loss, more preferably 10% by weight or less to the total weight ofthe rinse cleaning agent.

The rinse cleaning process satisfactorily comprises putting a cleaningsubject material in contact to the cleaning solvent, according togeneral cleaning processes. Specifically, the cleaning processes includehand wiping, immersion, spraying, and showering; immersion process isparticularly preferably used. For immersion treatment, physical meanssuch as ultrasonic vibration, shaking, agitation, and brushing can beused in combination. These rinse cleaning processes can be used singlyor in combination with two or more thereof. The temperature of the rinsecleaning solvent may appropriately be selected, depending on theproperties of the cleaning subject material. Generally, the temperatureis within a range of ambient temperature to the boiling point thereof,preferably 40° C. or more to the boiling point, and more preferably 50°C. or more to the boiling point.

(3) Separation process

The rinse cleaning agent for use in rinse cleaning in the process 2above is concentrated during use in repetition, leading to the decreaseof the rinse cleaning power. Thus, the concentrated cleaning agentshould necessarily be removed. The method for removing the agentincludes two-layer separation method and distillation separation method.

As to the two-layer separation method, due to the difference in specificgravity between the hydrocarbon used in the process 1 and the cyclictrihydrofluorocarbon used in the process 2, the upper hydrocarbon layeris separated from the lower cyclic trihydrofluorocarbon layer. Thehydrocarbon can be removed by adding fresh cyclic trihydrofluorocarbonto the same container to overflow and remove the upper hydrocarbonlayer. A method is preferably performed, comprising transferring a partof the rinse cleaning solvent in the process 2 to another container,where two layers, namely a hydrocarbon layer and a cyclictrihydrofluorocarbon layer, are separated from each other, andrecovering the cyclic trihydrofluorocarbon layer as the lower layer andrecycling the layer into the rinse cleaning solvent in the process 2.For two-layer separation, centrifugation process may satisfactorily beused.

The cyclic trihydrofluorocarbon for use in accordance with the inventionhas such a property that the cyclic trihydrofluorocarbon greatlydissolves hydrocarbon at high temperature but hardly dissolveshydrocarbon at low temperature, like hydrofluorocarbon andperfluorocarbon. Accordingly, the two-layer separation procedure ispreferably conducted at a lower temperature; the procedure is generallycarried out at a temperature lower by 10° C. or less, preferably 20° C.or less, more preferably 30° C. or less than the temperature of therinse cleaning solvent. The lower limit temperature for the two-layerseparation procedure is preferably above the melting point of thehydrocarbon or cyclic trihydrofluorocarbon. The method for cooling therinse cleaning solvent is with no specific limitation, and any of thefollowing methods can be used; a method comprising leaving the solventto stand at ambient temperature, a method comprising cooling the solventwith a cooling medium, and a method comprising partially evaporatingcyclic trihydrofluorocarbon and cooling the solvent by means of theevaporation heat. The cooling velocity is with no specific limitation.From the standpoints of efficiency and the prevention of the loss of thecleaning solution, however, active cooling methods such as cooling fromoutside and evaporation under reduced pressure are recommended.

As a rinse cleaning solvent at the process 2 or as a vapor cleaningsolvent at the process 4 described below, the cyclictrihydrofluorocarbon layer recovered through the two-layer separationcan be used, as it is or after treatment by distillation, filtration,active charcoal process and drying, if necessary.

Generally, it is very difficult to separate the cleaning agentcomprising a substance excluding hydrocarbon into two layers of cyclictrihydrofluorocarbon and a cleaning solvent. Hence, separation bydistillation is preferable.

(4) Vapor cleaning process

Vapor cleaning can be carried out in a conventional manner. The vaporcleaning solvent is with no specific limitation. Any vapor cleaningsolvent for use in general vapor cleaning can be used with no specificlimitation. Because the cyclic trihydrofluorocarbon recovered at theprocess 3 is highly pure, the cyclic trihydrofluorocarbon can be used asa vapor cleaning solvent, in accordance with the invention; after vaporcleaning, furthermore, the cyclic trihydrofluorocarbon can be circulatedas a rinse cleaning solvent at the process 2.

FIG. 1 depicts one example of the cleaning apparatus for the processesdescribed below.

A cleaning subject material with deposited staining substances such asoil, wax and flux, is immersed in a cleaning agent placed in firstcleaning vessel 1, where the staining substances deposited on thesurface of the cleaning subject material are removed. The cleaningsolvent placed in the cleaning vessel 1 can be heated with heatingapparatus 9 or cleaned in an ultrasonic manner by means of ultrasonicoscillation apparatus, if necessary, for improving the cleaning power.

When sufficient cleaning effect cannot be yielded in the cleaning vessel1, the material can be cleaned in cleaning vessel 2. In the cleaningvessel 2 as in the cleaning vessel 1, if necessary, heating andultrasonic cleaning can be additionally carried out. FIG. 1 depicts twocleaning vessels, but one vessel may be used or two or more vessels maybe used in combination, with no specific limitation.

The cleaning subject material, on which the cleaning solvent isdeposited after completion of cleaning, is then immersed in a rinsecleaning solvent comprising cyclic trihydrofluorocarbon as the principalcomponent and being placed in rinse cleaning vessel 3. If necessary forimproving the rinse cleaning power, therein, ultrasonic cleaning withultrasonic oscillation apparatus 10 may be carried out concurrently withshower rinsing or shaking rinsing.

The cleaning agent deposited on the surface of the cleaning subjectmaterial is separated from the surface of the cleaning subject material.The separated cleaning agent is transferred, via rinse solution transferpump 14 or overflowing or the flow of another additional rinse cleaningsolvent, into separator 4 or distillation column 15.

In accordance with the invention, furthermore, the cyclictrihydrofluorocarbon as the principal component of the rinse cleaningsolvent can exert high dissolution power of a cleaning agent in the hightemperature zone, so heating with the heating apparatus 9 is preferablebecause the rinse cleaning effect is prominently improved then. Due tothe supply of fresh cyclic trihydrofluorocarbon from circulation pump 11or 12, the rinse cleaning solvent can be retained at a homogenous statein the rinse cleaning vessel 3, whereby no cleaning agent layer isformed on the upper layer; thus, the most serious conventional drawbackof such type of apparatuses, namely re-deposition of the cleaning agentin the upper layer on the cleaning subject material when drawn out canbe overcome. After use, the homogenous rinse cleaning solvent istransferred into the separator 4 or distillation column 15 in the samemanner as described above.

In the separator 4, the upper layer of the cleaning agent layer 6 andthe lower layer of the cyclic trihydrofluorocarbon layer 7 are separatedfrom each other. By lowering the temperature of the separator 4, thepurity of the recovered cyclic trihydrofluorocarbon can be elevated andthe contamination of cyclic trihydrofluorocarbon into the hydrocarbonlayer can be reduced, remarkably. Therefore, the two-layer separationprocedure is generally carried out at a temperature lower by 10° C. orless, preferably 20° C. or less, more preferably 30° C. or less than thetemperature of the rinse cleaning vessel 3.

The cyclic trihydrofluorocarbon layer 7 as the lower layer of the thusseparated two layers is circulated via circulation pump 11 into rinsecleaning vessel 3 or via circulation pump 12 into vapor cleaning vessel5.

Vapor cleaning is used when a high cleaning level is demanded or whenthe consumption of cyclic hydrofluorocarbon should be reduced. In thiscase, the cyclic hydrofluorocarbon recovered via the circulation pump 12is transferred into vapor cleaning vessel 5 and heated with the heatingapparatus 9, to form vapor zone 8. Alternatively, the cleaning subjectmaterial after drawn out from the rinse cleaning vessel 3 is vaporcleaned in the vapor zone 8 of the cyclic hydrofluorocarbon.

The cyclic hydrofluorocarbon used in vapor cleaning is transferred,through coagulation or overflowing, into rinse cleaning vessel 3, wherethe cyclic hydrocarbon is again used.

FIG. 1 schematically shows one example of the apparatus for use incarrying out the inventive cleaning method; and the details of theindividual cleaning process, rinse cleaning process, two-layerseparation process and vapor cleaning process are not limited to theembodiments described above. In accordance with the invention, othergeneral methods can be used. If necessary, the numbers of cleaning andrinsing can be increased or decreased.

The action of the inventive fluorinated hydrocarbon or the cyclictrihydrofluorocarbon composing the same in cleaning for example isprominent from the respects of the cleaning potency and the stability.For example, the cleaning action of heptafluorocyclopentane (HFCPA) ascyclic trihydrofluorocarbon is at the same excellent level as that ofoctafluorocyclopentane (OFCPA) as dihydrofluorocarbon, while thestability thereof is far more greater than the stability ofoctafluorocyclopentane. Octafluorocyclopentane (OFCPA) is readilydecomposable in the presence of basic compounds, water or heat.

Other than the application to cleaning as described above, the inventivefluorinated hydrocarbon and cyclic trihydrofluorocarbon composing thesame, are as useful as liquid compositions for forming lubricatingpolymer film for electronic device, machine and apparatus. Thesehydrocarbons are used in liquid forms dispersing or dissolving polymerssuch as fluoropolymers, silicon containing resins, phenol resins, andpolyolefin resins. In such manner, a polymer film capable of greatlyreducing the frictional force against solid surface can be formed.

Polymers

In accordance with the invention, any polymer material with film formingpotency is used with no specific limitation, as long as the material canform a film on solid surface. Herein the term film includes completelyhomgenous film in a continuous phase such as those formed from a polymersolution but also includes nearly homogenous film in an incompletelycontinuous phase of individual polymer particles, such as those formedfrom a dispersion of numerous polymer particles. It is not required thatthe polymer has specific properties. The polymer may satisfactorily haveproperties conventionally required for film formation, such aslubricating properties, non-coherent properties, or liquid repellency(water repellency or oil repellency).

The polymer with film forming property includes for examplefluoropolymer, silicone resin, phenol resin, and polyolefin resin. Amongthem, preference is given to fluoropolymer.

Any fluoropolymer with a fluorine atom within the molecule issatisfactory, with no specific limitation, and includes for examplefluoropolymers and chlorinated, fluorinated olefin polymers. Specificpreferable examples of the fluorinated polymer includepolytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinylether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer(FEP), tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinylether copolymer (EPE), tetrafluoroethylene-ethylene copolymer (ETFE),polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylenecopolymer (ECTFE), polyvinyledene fluoride (PVDF) and polyvinyl fluoride(PVF). Among them, a homopolymer or copolymer or tetrafluoroethylene ispreferable.

In accordance with the invention, fluoropolymers containing hetero atomsare preferably used. The hetero atoms mean atoms belonging to the Group5B or 6B in the second to fourth periods in the periodic table,specifically including nitrogen atom, oxygen atom, sulfur atom andphosphorus atom. Oxygen atom is preferable. The fluorine-series polymerscontaining such hetero atoms include for example perfluoroalkylsulfonatepolyesters, perfluoroalkyl polyethers, polyimides with perfluoroalkylgroups, and partially fluorinated modified silicon oils. Among them,perfluoroalkyl polyethers are particularly preferable.

Any of perfluoroalkyl polyethers for general use as materials for filmformation is satisfactory, with no specific limitation;perfluoro-polyethers described in for example JP-A-61-126627,JP-A-63-97264, JP-A-4-211959, JP-A-5-342570 and JP-A-7-182652 can beused. Preferable perfluoro-polyethers include for example thoserepresented by general formulas, such as CH₂O—(CF₂CF₂O)n—CH₃,PhOCH₂OCH₂O—(CF₂CF₂O)n—CH₃, CF₃—[(OCF(CF₃)CF₂)n—(OCF₂)m]—OCF₃,CF₃—[(OCF₂CF₂)n—(OCF₂)m]—OCF₃ wherein Ph represents phenyl group.

Additionally, fluoropolymers with cyclic structures in the principalchains thereof, including for example cyclic fluorochlorocarbon polymersprepared by substituting a part of the fluorine atoms in cyclicperfluorocarobn, cyclic perfluoroether or cyclic perfluorocarbon withchlorine atoms, can be used as well. Examples of the fluoropolymers withcyclic structures in the principal chains include polymers with variousrepeat units as represented by the following formulas.

(wherein k=0 to 5; m=0 to 4; n=0 to 1; k+m+n=1 to 6; R represents F orCF₃.)

(wherein o, p, q=0 to 5; o+p+q=1 to 6.)

(wherein R₁ represents F or CF₃; R₂ represents F or CF₃.)

Specific examples of the repeat units as represented by the abovementioned individual general formulas include repeat units representedby the following formulas.

The cyclic perfluorocarbon and cyclic perfluoroether may satisfactorilybe copolymerized with other monomers. Specific examples of the monomersto be copolymerized include.

CF₂═CF—O—CF₂CF(CF₂)—O—CF₂CF₂SO₂F, CF₂═CF—O—CF₂CF₂CF₂COOCH₃, CF₂═CF—CF₃,CF(CF₃)₂—O—CF₂CF₂SO₂F, NH₂CO(CH₂)₂Si(OC₂H₅)₃

Additionally, the fluoropolymers include the polymers 1 to 9 describedbelow, such as those described in JP-A-64-31642.

(1) Copolymer of C₈F₁₇SO₂N (C₃H₇) CH₂CH₂OCOC (CH₃)=CH₂ withfluorine-free alkyl methacrylate.

(2) Copolymer of C_(n)F_(2n+1)CH₂CH₂OCOCH=CH₂ (n=1 to 16) orC_(n)F_(2n+1)CH₂OCOCH=CH₂ (n=1 to 4) or C_(n)F_(2n+1)OCOCH=CH₂ (n=2 to8) and methyl methacrylate at a molar ratio of 2:1 to 4:1.

(3) Polyurethane comprising C₁₀F₂₁CH₂CH₂OH, PPG-5000 and tolylenediisocyanate at a molar ratio of 2:1:2.

(4) Polyester comprising C₈F₁₇SO₂N (CH₂CH₂OH)₂, polyethylene glycol andadipic acid at a molar ratio of 1:3:4.

(5) Copolymer of CF₂=CFCl, CH₂=CH (OC₂H₅) and CH₂=CH (O(CH₂)₂OH) at amolar ratio of 5:5:1.

(6) Copolymer of CF₂=CFCl and CH₂=CH₂ at a molar ratio of 1:1.

(7) Copolymer of CF₂=CFCF₃ and CH₂=CHOCH₃ at a molar ratio of 1:1.

(8) Polyurethane comprising HOCH₂CF₂O (CF₂CF₂O)₁₈ (CF₂O)₂₃CF₂CF₂OH,stearyl alcohol and tolylene diisocyanate at a molar ratio of 1:2:2.

(9) Unsaturated polyester comprising (CF₃)₂C (C₆H₄OH)₂ or bisphenol Awhere at least one hydrogen atom in the phenol group is substituted withfluorine atom, adipic acid and fumaric acid at a molar ratio of 10:9:1.

The average molecular weight (number average molecular weight) of thefluorine-series polymer is with no specific limitation and isappropriately selected within a range of generally 1,000 to 5,000,000preferably 1,000 to 1,000,000, more preferably 1,000 to 500,000. Forexample, the average molecular weight of the above mentionedperfluoroalkyl polyether is within a range of generally 1,000 to100,000, preferably 1,000 to 50,000, more preferably 1,000 to 20,000.The molecular weights of the polymers 1 to 8 as described inJP-A-64-31642 are preferably 2,000 to 20,000 for polymer 1; 2,000 to40,000 for polymer 2: about 5,900 for polymer 3; about 4,700 for polymer4; about 3,000 for polymer 5;about 5,000 for polymer 6; about 8,000 forpolymer 7; and about 15,000 for polymer 8. The liquid medium containingcyclic trihydrofluorocarbon for use in accordance with the invention sohighly disperses polymer particles that these polymers maysatisfactorily be dispersed in the form of particles. More specifically,by dispersing polymer particles in a liquid medium comprising a cyclicfluorinated hydrocarbon and coating the resulting dispersion on solidsurface, thereby depositing the particles in dispersion in the form offilm, a film of the polymer particles can be recovered, with greathomogenous dispersibility of secondary particles, a small particle sizedistribution width of secondary particles, and a small frictionalcoefficient. The particle size of the polymer particles is appropriatelyselected, depending on the purpose of the use, but generally, theparticle size is 0.1 to 50 μm; the particle size is within a range ofpreferably 0.01 to 10 μm, more preferably 0.01 to 5 μm.

A film can be formed by dissolving a polymer in a liquid mediumcontaining cyclic trihydrofluorocarbon and coating the resultingsolution on solid surface; in this case, however, the form of thepolymer used is not specifically limited but includes a particle form, agrease form and a wax form.

The polymers with film formation potency can be used singly or incombination with two or more thereof.

Formulation ingredient

As disclosed in JP-A-7-182652 and JP-A-7-182653, formulation ingredientssuch as lubricating agents can be added to the polymers, if necessary,for the purpose of further reducing the frictional coefficients.

The lubricating agents include for example mineral oils such as paraffinoil, aroma oil, and naphthene oil; silicone oil; higher alcohols such aslauryl alcohol, tridecyl alcohol, cetyl alcohol, stearyl alcohol, oleylalcohol, eicosyl alcohol and cetyl alcohol; higher fatty acids such astridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid,margaric acid, stearic acid, nonadecanoic acid, and arachic acid, andsalts thereof with Li, Na, K, Mg, Ca and Ba; higher fatty acid esterssuch as methyl myristate, ethyl myristate, isopropyl pentadecanate,methyl palmitate, hexyl palmitate, butyl margarate, methyl stearate,ethyl stearate, propyl stearate, isopropyl stearate, butyl stearate,amyl stearate, isoamyl stearate, and hexyl stearate; andfluorine-containing silane compounds such as CF₃(CH₂)₂Si(CH₃)Cl₂,CF₃(CH₂)₂Si(OCH₃)₃, CF₃(CF₂ ₅(CH₂)₂SICl₃, CF₃(CF₂ ₇(CH₂)₂Si(CH₃)₂Cl,CF₃(CH₂)₇(CH₂)₂Si(OCH₂CH₃)₃, CF₃(CF₂)₅(CH₂)₂Si(NH₂)₃. Among them,preference is given to mineral oil, silicon oil, higher alcohol, higherfatty acid, higher fatty acid salt and higher fatty acid ester.

The amount of the lubricating agent to be used is appropriately selectedwithin a range with no deterioration of the characteristic properties ofthe resulting polymer film; the amount is generally 0.01 to 50 part(s)by weight, preferably 0.1 to 30 part(s) by weight, more preferably 1 to15 part(s) by weight to 100 parts by weight of the polymer.

Coating subject solid

With no specific limitation, any solid can be used as a coating subjectwith a polymer-containing solution and is selected, depending on thepurpose of the use. The materials of such coating subject solid includefor example rubbers such as natural rubber, isoprene polymer, butadienepolymer rubber (BR), styrene-butadiene copolymer rubber (SBR),hydrogenated styrene-butadiene copolymer rubber (hydrogenated SBR),acrylonitrile-butadiene copolymer rubber (NBR), hydrogenatedacrylochloroprene polymer rubber (CR), and silicon rubber; metals suchas aluminum, iron stainless, titanium and copper; and inorganicmaterials such as SiO, SiC, carbon, glass, ceramics and silicon; andresins such as polycarbonate, polyimide, polysulfone, polyester,polyether sulfone polyester, polyphenylene sulfide, polyurethane,polyolefin, Bakelite, and polyacetal photosensitive resin.

The polymer-containing solution of the invention is useful in coatingmagnetic base materials.

As the magnetic base materials, use can be made of various non-magneticbase materials overlaid, directly or through an underlying layer such asnickel/phosphorus, titanium, silicon, and anodized aluminum, with asingle ferromagnetic metal film or two or more such films.

As the ferromagnetic metal film, use can be made of Co, Co-Ni, Co-Cr,Co-Fe, Co-Ni-Cr, Co-Ni-Fe, Co-Ni-P and Co-Ni-Ta or partially oxidizedforms thereof. These films can be formed by vacuum deposition,sputtering, ion plating and plating. If necessary, additionally,underlying layers of Cr or Ti may satisfactorily be arranged; and thethickness of the ferromagnetic metal film including the underlying layeris generally 0.005 μm to 100 μm, preferably 0.01 μm, to 50 μm.

If necessary, protective film layers generally used for general magneticrecording media can be formed on the surface of the ferromagnetic metalfilm, which is then put to use. As such protective layers, for example,the following layers can be formed; metal protective film layers of Cr,W, and Ni; inorganic protective film layers of SiO, SiC, carbon,graphite, and diamond-like carbon (JP-A-5-342570 and JP-A-61-126627);organic protective layers comprising linear saturated fatty acids with 8to 28 carbon atoms, and salts thereof with alkali metals (Li, Na, K andthe like) or alkali earth metals (Mg, Ca, Ba and the like)(JP-B-56-30609); silicone resin (JP-A-61-131231), epoxy resin, polyamideresin, plasma-induced polymerization product, and radiation-inducedpolymerization product; or complex protective layer. These protectivefilms can be used singly or in combination with two or more layersoverlaid together. The film thickness of the protective layer isappropriately selected, depending on the use, which is generally 0.01 to0.1 μm, preferably 0.005 to 0.05 μm.

Specific examples of the coating subject solid comprising the materialsdescribed above, include inkjet record head, cleaning blade of officemachines, for example rubber cleaning blade for removing residual toneron the photosensitive material of electrophotographic copy machine, thesliding parts of camera, office machines, medical apparatuses, precisionmachine, vacuum apparatuses such as vacuum pump, electronic parts,precision automobile parts, small motor, ultrasonic motor andmicro-machine, magnetic record media of various magnetic disks such ashard disk and digital video tape, optical disk, and the space betweenfilm and rubber or resin sheet.

The form of the coating subject solid is not specifically limited, butspecifically includes for example any of plate form, film form, particleform and fiber form.

Polymer-containing solution

So as to dissolve or disperse the polymer or the polymer together with aformulation ingredient in a solvent containing cyclictrihydrofluorocarbon, the polymer is placed in a liquid medium andagitated therein, satisfactorily. If necessary, means such as heatingand ultrasonic irradiation can be used.

The content of the polymer in the inventive polymer-containing solutionis appropriately selected, depending on the type of the polymer, thecoating subject solid, the coating processability and the filmthickness; the content is within a range of generally 0.0001 to 50% byweight, preferably 0.001 to 10% by weight, more preferably 0.005 to 5%by weight on the basis of the weight of solution (total weight of theliquid medium and the polymer). For coating on hard disk, for example, asolution at such a low concentration of 0.01 to 1% by weight isparticularly preferable. Depending on whether or not the polymer isdissolved or dispersed in the liquid, the preferable concentration ofthe polymer varies. More specifically, when the polymer is dissolved inthe liquid, the content is within a range of 0.0001 to 10% by weight,preferably 0.001 to 1% by weight, more preferably 0.005 to 0.5% byweight on the basis of the weight of solution (total weight of theliquid medium and the polymer). When the polymer is dispersed in theliquid, the content is within a range of generally 0.01 to 20% byweight, preferably 0.1 to 10% by weight, more preferably 0.5 to 5% byweight on the same basis.

Treatment of solid surface

A polymer film can be formed by coating the polymer-containing solutionon solid surface and then removing the liquid medium.

The method for coating a dispersion or solution containing a polymersuch as fluoropolymer is carried out in a conventional manner andincludes for example, dipping, spin coating and spraying. The liquidmedium contained in the coated film of the polymer-containing solutionis generally removed by drying at ambient temperature or under heatingin an inactive gas such as nitrogen gas or in atmosphere. Heating may becarried out in vacuum at a pressure of 10⁻¹ Torr or less. Additionally,the removal of the liquid medium can be promoted by irradiation of lightor electron beam for transferring the energy.

After drying the coated film, if desired, energy transfer from heat,light or electron beam can elevate the polymerization degree offilm-composing polymers, such as fluoropolymers, or can induce crosslinking therein.

The thickness of the polymer film is within a range of generally 0.0001to 10 μm, preferably 0.0005 to 5 μm, more preferably 0.001 to 3 μm.Furthermore, the film thickness varies, depending on the use. The filmthickness of the polymer film to be formed on inkjet record head isgenerally 0.001 to 10 μm, preferably 0.005 to 5 μm, and more preferably0.01 to 2 μm; the film thickness of the polymer film to be formed on thecleaning blade of electrophotographic copy machine is generally 0.01 to10 μm, preferably 0.01 to 5 μm, and more preferably 0.1 to 5 μm; and thefilm thickness of the polymer film to be formed on magnetic record harddisk is generally 0.0001 to 10 μm, preferably 0.0001 to 5 μm, and morepreferably 0.0005 to 3 μm.

The invention is now more specifically described in the followingexamples. It is needless to say that the invention is not limited tothese examples.

<SYNTHESIS> EXAMPLE 1 (Synthesis of1,1,2,2,3,3,4-heptafluorocyclopentane)

Octafluorocyclopentane (at a purity of 99.9%, 42.4 g, 200 mmol) and 5%palladium carbon (2.12 g) were charged in a 70 ml-autoclave fitted withan agitator, for hydrogenation a hydrogen pressure of 6 kg/cm² at 50° C.Fifteen hours later when hydrogen consumption was completely ceased,heating was terminated to stop the reaction. After sufficientneutralization with saturated sodium bicarbonate solution, the organiclayer was separated, followed by addition of 200 ml of an aqueous sodiumcarbonate solution at a concentration of 1 mol. The resulting mixturewas agitated at 30° C. for 10 hours. The reaction solution was separatedinto two layers; the resulting organic layer was again charged, togetherwith 5% palladium carbon (1.78 g) and 1 g of tridecane, in a 70ml-autoclave, for hydrogenation at 50° C. under a hydrogen pressure of 6kg/cm². When hydrogen absorption was ceased 15 hours later, the reactionwas terminated in the same manner as described above; then, theresulting solution was neutralized with saturated sodium bicarbonatesolution, followed by distillation, to recover1,1,2,2,3,3,3,4-heptafluorocyclopentane (at a purity of 99.0%; 34.0 g).

EXAMPLE 2 (Synthesis of 1,1,1,2,4,4,5,5,5-nonafluoropentane)

To 1,1,1,2,3,4,4,5,5,5-decafluoropentane (at a purity of 99.9%, 20 g,79.4 mmol) was added 100 ml of an aqueous 4M potassium carbonatesolution; and the resulting mixture was agitated at 30° C. for 10 hours.The reaction solution was separated into two layers; and the organiclayer was again charged, together with 5% palladium carbon (0.55 g) and0.33 g of tridecane, in a 70-ml autoclave, for hydrogenation at 50 ° C.under a hydrogen pressure of 6 kg/cm². When hydrogen absorption wasceased 15 hours later, the reaction was terminated; then, the resultingsolution was neutralized with saturated sodium bicarbonate solution,followed by distillation, to recover nonafluoropentane(1,1,1,2,4,4,5,5,5- and 1,1,1,3,4,4,5,5,5-nonafluoropentane mixture)(ata total purity of 99.7%; 10.4 g).

<CLEANING> EXAMPLE 3

Flux (PO-F-1010S; manufactured by Senju Kinzoku K.K.) was coated on thewhole surface of a printed circuit board (30 mm ×30 mm×0.2 mm inthickness) made of a polyimide resin, which was then dried at ambienttemperature. The resulting board was immersed in1,1,2,2,3,3,4-heptafluorocyclopentane at a purity of 96% at 30° C. for 3minutes. The extent of flux removal was visually observed. It wasconfirmed that the flux was completely removed.

EXAMPLE 4

Fifty sheets of a press-processed part (a 50-mm square made ofstainless) were aligned together and bound with a wire; and theresulting stack was immersed in a beaker charged with a press oil(Daphne punch oil manufactured by Idemitsu Kosan, Co., Ltd.) at ambienttemperature, followed by ultrasonic application for one minute so as toentirely immerse the stack in the press oil. After the stack was left tostand in the oil as it was for 30 minutes, the stack was drawn out ofthe press oil and left to stand for 5 minutes for oil draining. Thesample was immersed in 1,1,2,2,3,3,4-heptafluorocyclopentane at a purityof 96% under ultrasonic application at 50° C. for 3 minutes and wasfurther vapor cleaned in the vapor of1,1,2,2,3,3,4-heptafluorocyclopentane at the same purity of 96%. Aftercooling, the extent of oil removal was visually observed, while the odorwas checked. It was confirmed that the oil was completely removed.

EXAMPLES 5 to 8 COMPARATIVE EXAMPLES 1 to 8

Rosin-series fluxes (Table 2) were coated on printed circuit boards (1.6mm×69 mm×95 mm) (Table 1), which were then dried preliminarily, followedby heating at 200° C. for 3 minutes. The resulting boards were used astest pieces.

These test pieces were immersed in 1,1,2,2,3,3,4-heptafluorocyclopentane(HFCPA) containing 10% ethanol at ambient temperature, for ultrasoniccleaning for one minute (at an output of 50%; 60 w and 35 kHz).

Alternatively, cleaning with CFC 113 and perfluorohexane was conductedin Comparative Examples.

The effect on the removal of the Rosin fluxes and the influence thereofon the print boards were visually observed; and the results are shown inTable 3.

Consequently, it is indicated that HFCPA containing 10% ethanol exertedthe cleaning effect at the same level as or a higher level than thelevel of the cleaning performance of CFC 113 and PFC conventionallyused.

TABLE 1 Type name Material IC-301-62 Phenol × PC IC-701-62 Glass epoxy

manufactured by Takasu Electronic Industries.

TABLE 2 Name Manufacturer NS-829 Nippon Superior Co., Ltd. R5003 NipponAlpha-Metals, Co., Ltd.

TABLE 3 Cleaning Test Cleaning agent Board material Flux performanceExample 5 HPCPA IC-301-62; NS-829 ◯ phenol × PC Example 6 HFCPAIC-301-62; R5003 ◯ phenol × PC Example 7 HFCPA IC-701-62; NS-829 ◯ glassepoxy Example 8 HFCPA IC-701-62; R5003 ◯ glass epoxy Comparative CFC 113IC-301-62; NS-829 ◯ Example 1 phenol × PC Comparative CFC 113 1C-301-62;R5003 ◯ Example 2 phenol × PC Comparative CFC 113 IC-701-62; NS829 ◯Example 3 glass epoxy Comparative CFC 113 IC-701-62; R5003 ◯ Example 4glass epoxy Comparative perfluorohexane 1C-301-62; NS-829 Δ - x Example5 phenol × PC Comparative perfluorohexane IC-301-62; R5003 Δ - x Example6 phenol × PC Comparative Perfluorohexane IC-701-62; NS-829 Δ - xExample 7 glass epoxy Comparative perfluorohexane IC-701-62; R5003 Δ - xExample 8 glass epoxy Cleaning performance: ◯; appropriate, Δ; poor, x;not good.

EXAMPLES 9 to 13

As shown in FIG. 1, a double-vessel cleaning machine (cleaning vessel 1and cleaning vessel 2) equipped with heating apparatus 9 and ultrasonicoscillation apparatus 10 was charged with NS Clean 230 (a C13hydrocarbon-series cleaning agent; manufactured by Nikko PetroleumChemical Industries, Co.). The resulting vessel was designated ascleaning vessel; rinse cleaning machine (rinse cleaning vessel 3)equipped with heating apparatus 9 and ultrasonic oscillation apparatus10 was charged with 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCPA);furthermore, cyclic hydrofluorocarbon recovered in separator 4 wastransferred into a vapor cleaning apparatus (vapor cleaning vessel 5)equipped with cooling tube 13 and was then heated with the heatingapparatus 9, to generate vapor zone 8. Herein, the temperature of theseparator 4 was controlled to 25° C.

Cleaning subject materials were prepared by dissolving stainingsubstances in Table 4 at 25% in 1,1,1-trichloroethane, additionallyadding a tracer sudan dye at 0.1% by weight to the resulting solution,and immersing materials shown in Table 4 in the resulting mixture todeposit the staining substances thereon. The amount of the stainingsubstances deposited was determined, on the basis of the difference inweight between prior to and after immersion.

At subsequent cleaning tests of the cleaning subject materials, thematerials were subjected to the following procedures sequentially in thecleaning vessel 1, cleaning vessel 2, rinse cleaning vessel 3 and vaporcleaning vessel 5.

1. Cleaning tank 1: cleaning subject materials were immersed in thisvessel at 50° C., for 3-min ultrasonic application.

2. Cleaning vessel 2: cleaning subject materials were immersed in thisvessel at 50° C. for 1-min ultrasonic application.

3. Rinse cleaning vessel 3: cleaning subject materials were immersed inthis tank for 50° C., for 1-min ultrasonic application.

4. Vapor cleaning vessel 5: cleaning subject materials were placed inthe vapor zone 8 of the vapor cleaning vessel 5 at 80° C. as the boilingpoint of the recovered 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCPA) for2 minutes.

After the cleaning tests, the cleaning subject materials were evaluatedby the following methods. The results are also shown in Table 4.

<A>Amount of residual staining substances

After cleaning, the cleaning subject materials were treated with a givenamount of purified 1,1,1-trichloroethane; extracting the residualstaining substances and the dye and measuring the absorbance of sudanred, the residual amount thereof was determined on the basis of astandard curve. The residual amount divided by the amount of themeasured deposited amount was shown as residual ratio (%).

<B>Visual evaluation

After cleaning, the cleaning subject materials were observed andassessed on the following standards.

O: no stain observed.

Δ: slight stain observed.

x: apparent stain observed.

<C>Evaluation of odor

After cleaning, the odor of the cleaning subject materials was checkedand evaluated on the following standards.

O: no oil odor smelled.

Δ: slight oil odor smelled.

x: apparent oil odor smelled.

COMPARATIVE EXAMPLE 9

In the same manner as in Example 10 except that the rinse cleaningsolvent was changed to vic-dihydrofluorocarbon, namely1,1,1,2,2,3,4,5,5,5-decafluoropentane (DFPA; boiling point of 55° C.), acleaning test was performed. The results are shown in Table 5.

COMPARATIVE EXAMPLE 10

In the same manner as in Example 10 except that the rinse cleaningsolvent was changed to a perfluorocarbon, namely perflurohexane (PFHX;boiling point of 56° C.), a cleaning test was performed. The results areshown in Table 5.

TABLE 4 Residual Visual Example Materials Stain amount observation Odor9 volt nut cutting oil 0.0% ◯ ◯ 10 glass epoxy flux 0.03%  ◯ ◯ resin 11glass bottle silicone oil 0.0% ◯ ◯ 12 printer blade oily ink 0.04%  ◯ ◯13 optical oil and fat 0.0% ◯ ◯ glass lens

TABLE 5 Comparative Residual Visual Example Fluorine-series solventamount observation Odor 9 1,1,1,2,2,3,4,5,5,5,5- 0.25% Δ xdecafluoropentane 10 perfluorohexane  0.5% Δ x

Tables 4 and 5 indicate that the inventive examples (Examples 9 to 13)exerted great results at the assessment of residual amount of stainingsubstances, visual assessment and odor assessment. On contrast, poorassessment results of residual amount of staining substances and odorare brought about when the linear hydrofluorocarbon was used as a rinsecleaning solvent (Comparative Example 9), indicating that the cleaningeffect of the hydrofluorocarbon was not sufficient. Poor assessmentresults of residual amount of staining substances and odor are broughtabout when the perfluorocarbon was used as a rinse cleaning solvent(Comparative Example 10), indicating that the cleaning effect of thehydrofluorocarbon was not sufficient.

EXAMPLE 14 COMPARATIVE EXAMPLE 11

The cleaning methods in Example 9 and Comparative Example 10 wererepeated 20 times; the cleaning power was then assessed; and the resultsare shown in Table 6.

TABLE 6 Residual Visual Solution state Test Fluorine-series solventamount observation Odor *1 Example 14 1,1,2,2,3,3,4- 0.01% ◯ ◯homogenous heptafluorocyclopentane Comparative 1,1,1,2,2,3,4,5,5,5- 0.5% x x separation Example 11 decafluoropentane into two layers (*1:Visually observed whether or not the rinse cleaning solvent washomogeneously dissolved or was separated into two layers with ahydrocarbon layer as the upper layer.)

The results of Table 6 indicate that the inventive example (Example 14)can retain sufficiently great rinse cleaning effect even after use inrepetition. On contrast, the rinse cleaning power was extremelydeteriorated when the linear hydrofluorocarbon was used as a rinsecleaning solvent. This may be due to the fact that the rinse cleaningsolvent was homogenous in Example 14, while in Comparative Example 11,the emerging hydrocarbon upper layer was possibly deposited again on thecleaning subject materials when they were drawn up.

<Polymers>

In the following examples and comparative examples, thepolymer-containing solution and the method for forming a polymer film inaccordance with the invention are now more specifically described. Inthe examples and comparative examples, the part and % are based onweight, unless otherwise stated.

Forming a polymer film on hard disk surface by using apolymer-containing solution with a polymer dissolved therein

On an aluminium hard disk substrate of which the surface was plated withnickel in an electrolytic manner was arranged a cobalt alloy magneticlayer; 5 sheets of the hard disk, additionally arranged with a carbonlayer of a thickness of about 200 angstroms, were vertically aligned ata given interval in an immersion tank; then, polymer-containingsolutions described in Examples 15 and 18 and Comparative Examples 12and 13 were heated at 35° C. and poured gradually in the tank. Thepolymer-containing solutions were poured at such a velocity that theentire surfaces of the hard disks might be immersed in the solutionsover 2 minutes; after the hard disks were left to stand for 2 minutes,the hard disks were gradually drawn out of the immersion tank over 2minutes. Subsequently, the hard disks were dried.

Evaluation of polymer film formed on hard disk surface by usingpolymer-containing solutions with polymers dissolved therein

(1) Thickness of polymer film

By using an inter-atomic force microscope, the thickness of polymer filmwas measured at 5 points along a line drawn from the disk center towardthe circumference. For the measurement, etching a part of the polymerfilm formed on the hard disk surface with a solvent to remove thepolymer, thereby exposing the underlining carbon layer to the hard disksurface, the resulting hard disk surface was defined as zero base fordetermining the thickness of polymer film. The results are shown inTable 7.

TABLE 7 Polymer thickness (×10⁻⁴ μm) maxi- mini- mean of values Presenceor absence of Test mum mum at 5 points superficial wrinkle Example 15 2121 21 no Example 16 26 25 26 no Example 17 22 22 22 no Example 18 23 2222 no Comparative 25 21 22 many wrinkles along Example 12 circumferencedirection Comparative 55 22 28 irregular, large recesses and Example 13protrusions with many wrinkles

(2) Observation of Surface State of Polymer Film

By observing the hard disk surface with an inter-atomic forcemicroscope, the presence or absence of wrinkles on the surface of aformed polymer film was observed. The results are shown in Table 7.

(3) CSS Test

After sufficiently drying the polymer film on the hard disk, the initialfrictional coefficient was measured at a CSS number of 15,000, togetherwith the CSS number when the initial frictional coefficient wasincreased, by using a CSS (contact start stop) tester. The results areshown in Table 8.

TABLE 8 CSS number (recording CSS number Initial frictional when theinitial frictional Test coefficient coefficient was increased) Example15 0.42 The value of the initial frictional coefficient was maintainedup to 15000. Example 16 0.40 The value of the initial frictionalcoefficient was maintained up to 15000. Example 17 0.43 The value of theinitial frictional coefficient was maintained up to 15000. Example 180.44 The value of the initial frictional coefficient was maintained upto 15000. Comparative 0.65 about 12000. Example 12 Comparative largevariation about 2500. Example 13 at about 1 to 3

Formation of Polymer Film on Rubber Sheet Surface by UsingPolymer-Containing Solution With Polymer Dispersed Therein

On a sheet of nitrile hydride rubber (acrylonitrile hydride-butadienecopolymer rubber, manufactured by Nippon Zeon) were coated dispersionsdescribed in Example 20 and Comparative example 14 by spraying;subsequently vaporizing and removing the solvents and further drying thesheet in hot air at 60° C. to disperse the polymer particles in a filmform, a rubber sheet with a polymer film formed thereon was recovered.

Evaluation of Polymer Film on Rubber Sheet Surface, as Formed by UsingPolymer-Containing Solution with Polymer Dispersed Therein

(1) Average Film Thickness

After sufficiently drying the polymer film on the rubber sheet, the filmthickness of the polymer film was measured at arbitrary 5 points on thepolymer film by means of eripsometer. The average film thickness isshown in Table 9.

TABLE 9 Comparative Example 19 Example 14 Mean film thickness (μm) 1.98.7 Dispersibility of polymer particles dispersibility of secondaryhomogenous homogenous particle particle size of secondary about 1 to 3about 1 to 30 particle distribution width (μm) Static frictionalcoefficient 1 0.5 0.9 2 0.4 1.1 3 0.5 0.8 4 0.4 1.1 5 0.5 0.9 Average0.46 0.96

(2) Dispersibility of Polymer Particles

After sufficiently drying the polymer film on the rubber sheet, thesurface of the polymer film was observed by SEM; the dispersion state ofsecondary particles prepared by particle coherent as well as theparticle size distribution of the secondary particles was evaluated. Theresults are shown in Table 9.

(3) Static Frictional Coefficient

After sufficiently drying the coated film of a fluorine-series polymeron the rubber sheet, 5 points were arbitrarily selected on the filmsurface; the static frictional coefficient at a sliding velocity of 1.5mm/sec was measured at ambient temperature by using a friction tester ofa pin-disk type. The results are shown in Table 9.

EXAMPLE 15

Demnum as a perfluoroether polymer (average molecular weight of 5600;manufactured by Daikin Industries, Co., Ltd.) was dissolved at a 0.2-%concentration in 1,1,2,2,3,3,4-heptafluorocyclopentane recovered inExample 1, which was defined as fluoropolymer-containing solution. Byusing the fluoropolymer-containing solution, a polymer film was formedon the hard disk, in the same manner as described above. The resultsshown in Table 7 indicate that the hard disk treated with thefluoropolymer-containing solution was at a small variation of thethickness of the fluoropolymer film, with no observed wrinkle on thesurface. Additionally, even the results in Table 8 indicate that thehard disk treated with the fluoropolymer-containing solution had a smallinitial frictional coefficient, while the CCS number thereof indicatessufficient durability.

EXAMPLE 16

In the same manner as in Example 15 except for the use of Phonbrine(average molecular weight of 9500; manufactured by Audimont Co., Ltd.)as a perfluoroether polymer, experiments were carried out. The resultsin Table 7 indicate that the hard disk treated with thefluoropolymer-containing solution was at a small variation of thethickness of the fluorine-series polymer film, with no observed wrinkleon the surface. Additionally, the results in Table 8 indicates that thehard disk treated with the fluoropolymer-containing solution had a smallinitial frictional coefficient, while the CCS number thereof indicatessufficient durability.

EXAMPLE 17

In the same manner as in Example 15 except for the use of1,1,2,2,3,3,4-heptafluorocyclopentane with addition of 10% by weight ofnonafluorobutyl methyl ether (HFE-7100, manufactured by 3M) as thesolvent for a polymer-containing solution, a polymer film was formed onthe hard disk surface. The results in Table 7 show that that the harddisk treated with the fluorine-series polymer-containing solution was ata small variation of th thickness of the fluoropolymer film with noobserved wrinkle on the surface. Additionally, the results in Table 8indicate that the hard disk treated with the fluoropolymer-containingsolution had a small initial frictional coefficient, while the CCSnumber thereof indicates sufficient durability.

EXAMPLE 18

In the same manner as in Example 15 except for the use of1,1,2,2,3,3,4-heptafluorocyclopentane with addition of 10% by weight of2,3,-dihydrodecafluoropentane (HFC-43-10 mee, manufactured by Dupont,Co.) as the liquid medium for a polymer-containing solution, a polymerfilm was formed on the hard disk surface. The results in Table 7 showthat that the hard disk treated with the fluoropolymer-containingsolution was at a small variation of the thickness of the fluoropolymerfilm, with no observed wrinkle on the surface. Additionally, the resultsin Table 8 indicate that the hard disk treated with thefluoropolymer-containing solution had a small initial frictionalcoefficient, while the CCS number thereof indicates sufficientdurability.

COMPARATIVE EXAMPLE 12

In the same manner as in Example 15 except for the use ofperfluoro-n-pentane instead of 1,1,2,2,3,3,4-heptafluorocyclopentane asthe liquid medium for a polymer-containing solution, a fluoropolymerfilm was formed on the hard disk surface. The results in Table 7indicate that wrinkles were observed on the surface of the hard disktreated with the fluoropolymer-containing solution along thecircumference direction, with a variation of the thickness of thefluoropolymer film. Furthermore, the results of the CCS test (Table 8)show that the frictional coefficient of the hard disk treated with thefluorine-series polymer-containing solution was larger than that inExample 1. Still furthermore, the initial frictional coefficient wasincreased at a CSS number of about 12,000, with no sufficient durabilityas observed in Example 15.

COMPARATIVE EXAMPLE 13

In the same manner as in Example 16 except for the use ofperfluoro-n-pentane instead of 1,1,2,2,3,3,4-heptafluorocyclopentane asthe liquid medium for a polymer containing solution, a fluoropolymerfilm was formed on the hard disk surface. At the stage of polymerdissolution, however, the polymer-containing solution turned turbid,which indicates that the polymer was not homogeneously dissolvedtherein. The results in Table 7 indicate that the thickness of thefluoropolymer film was at a large variation and that wrinkles weresignificant together with the presence of large recesses and protrusionson the surface of the hard disk treated with thefluoropolymer-containing solution. Furthermore, the results of the CCStest (Table 8) show that the initial frictional coefficient of the harddisk treated with the fluoropolymer-containing solution was increased ata CSS number of about 2500, with no sufficient durability as observed inExample 15.

EXAMPLE 19 AND COMPARATIVE EXAMPLE 14

Polytetrafluoroethylene particle (mean particle size of 0.5 μm) wasdispersed in a solvent composed of 95 parts by weight of1,1,2,2,3,3,4-heptafluorocyclopentane recovered in Example 1 and 5 partsby weight of nonafluorobutyl methylether (HFE-7100 manufactured by 3M,Co.), to prepare a polymer-containing solution in dispersion at a solidconcentration of 1.0%. The dispersion was dispersed and deposited in afilm form on the rubber sheet, to prepare a polymer film. Thecharacteristic properties of the polymer particle film were evaluated.The results are shown in Table 9.

In Comparative Example 14, a polymer film was formed on the rubber sheetin the same manner as in Example 19, except for the use ofperfluoro-n-heptane instead of the mixture of1,1,2,2,3,3,4-heptafluorocyclopentane and nonafluorobutyl methyl ether.The characteristic properties of the polymer particle film wereevaluated. The results are shown in Table 9.

As shown in Table 9, in the case of coating dispersions prepared bydispersing polymer particles in the inventive liquid medium containingtrihydrofluorocarbon on solid surface to disperse and deposit theparticles in a film form (Example 19), compared with the case of thelinear fluorine-series hydrocarbon used as the liquid medium(Comparative Example 14), a polymer film with a smaller average filmthickness, more homogenous dispersibility of secondary particles, asmaller particle size distribution width and a smaller static frictionalcoefficient can be recovered.

<Stability Test of Trihydrofluorocarbon>

Stability Test in Alkali

REFERENCE EXAMPLE 1

In a Pyrex glass tube (15 ml) were placed1,1,2,2,3,3,4-heptafluorocyclopentane (at a purity of 98.3%, 1.0 g), anaqueous potassium carbonate solution (at a concentration of 4 mol/l, 1.5ml) and tetrabutylammonium bromide (50 mg), and the resulting mixturewas agitated at 30° C. in a water bath. Two hours later, agitation wasceased; and the lower layer was analyzed by gas chromatography (263-70manufactured by Hitachi, Co., Ltd.). The results indicate that thedecomposition ratio of 1,1,2,2,3,3,4-heptafluorocyclopentane was 19.5%.

REFERENCE EXAMPLE 2

In a Pyrex glass tube (15 ml) were placed1,1,1,2,3,4,4,5,5,5-decafluoropentane (1.0 g), an aqueous potassiumcarbonate solution (at a concentration of 4 mol/l, 1.5 ml) andtetrabutylammonium bromide (50 mg), and the resulting mixture wasagitated at the same velocity as in Reference Example 1 at 30° C. in awater bath. Two hours later, agitation was ceased; and the lower layerwas analyzed by gas chromatography (263-70, manufactured by Hitachi,Co., Ltd.). The results indicate that the decomposition ratio of1,1,1,2,3,4,4,5,5,5-decafluoropentane was 40%.

REFERENCE EXAMPLE 3

In the same manner as in Reference Example 2 except for the use ofnonafluoropentane synthetically produced in Example 2, instead of1,1,1,2,3,4,4,5,5,5-decafluoropentane, experiments were carried out.Then, the decomposition ratio of nonafluoropentane was 18%.

REFERENCE EXAMPLE 4

In the same manner as in Reference Example 1 except for the use of1,1,2,2,3,3,4,5-octafluorocyclopentane instead of1,1,2,2,3,3,4-heptafluorocyclopentane, experiments were carried out.Then, the decomposition ratio of octafluorocyclopentane was 56.9%.

REFERENCE EXAMPLE 5

A mixture (10 g) of 65 parts by weight of1,1,2,2,3,3,4,5-octafluorocyclopentane instead of1,1,2,2,3,3,4-heptafluorocyclopentane and 35 parts by weight of1,1,2,2,3,3,4-heptafluorocyclopentane, an aqueous potassium carbonatesolution (at a concentration of 2.5 mol/l, 1.2 equivalents to1,1,2,2,3,3,4,5-octafluorocyclopentane), and tetrabutylammonium bromide(at 5% by weight of OFCPA) were placed, and the resulting mixture wasagitated at the same velocity as in Reference Example 1 at 30° C. in awater bath. Two hours later, agitation as ceased; and the lower layerwas analyzed by gas chromatography (263-70, manufactured by Hitachi,Co., Ltd.). The results indicate that the decomposition ratio of1,1,2,2,3,3,4-octafluorocyclopentane was 100%, while the decompositionratio of 1,1,2,2,3,3,4-heptafluorocyclopentane was 1.8%.

REFERENCE EXAMPLE 6

In a glass evaporation dish was placed 2 g of1,1,2,2,3,3,4-heptafluorocyclopentane (at a purity of 98.3%), to whichthe flame of a hand-type gas burner was brought close. The fluid wasonly evaporated by never burned.

REFERENCE EXAMPLE 7

In a glass evaporation dish was placed 2 g of1,1,2,2,3,3-hexafluorocyclopentane (at a purity of 99.9%), to which theflame of a hand-type gas burner was brought close. The fluid burned withred flame, and thereafter, the flame disappeared. Soot was deposited onthe wall surface of the evaporation dish.

REFERENCE EXAMPLE 8

In a glass evaporation dish was placed 2 g of1,1,2,2,3,3,4-heptafluorocyclopentane (at a purity of 98.3%) and 10 mgof Demnum as the perfluoroether-series polymer used in Example 16, towhich the flame of a hand-type gas burner was brought close. The fluidwas only evaporated by never burned.

By the same method as described above,1,1,2,2,3,3-hexafluorocyclopentane (at a purity of 99.9%) was tested.The fluid burned with red flame, and thereafter, the flame disappeared.Soot was deposited on the wall surface of the evaporation dish.

The results indicate that the incombustibility of the polymer-containingsolution in the liquid medium 1,1,2,2,3,3,4-heptafluorocyclopentane waselevated, compared with the incombustibility of a polymer-containingsolution in a liquid medium of tetrahydrofluorocarbon with a structure—CH₂—CH₂—, such as 1,1,2,2,3,3-hexafluorocyclopentane.

Purification and Recovery in Separator 4

REFERENCE EXAMPLE 9

In a 200-ml flask with a magnetic agitator was placed a mixture of 10 gof n-tridecane and 100 ml of 1,1,2,2,3,3,4-heptafluorocyclopentane, andthe temperature of the mixture was gradually elevated under agitation toheat the mixture to 75° C. and prepare a homogenous solution.Subsequently, the homogenous solution was transferred in the separator 4in FIG. 1 (at 20° C.). The solution turned opaque and was laterseparated completely into two layers. The lower layer was analyzed bygas chromatography. The purity of 1,1,2,2,3,3,4-heptafluorocyclopentanewas 98%, which indicates that the solvent was almost entirely purifiedand recovered.

Industrial Applicability

As has been described above in detail, the invention of the applicationcan provide a fluorinated hydrocarbon comprising a highly pure cyclictrihydrofluorocarbon, characterized in that the fluorinated hydrocarbonwith excellent cleaning action, incombustibility and high stability inthe presence of basic compounds and water, can be produced readily, acomposition thereof, and a cleaning agent and a cleaning method.

The fluorinated hydrocarbon in accordance with the invention of theapplication can absolutely be used as a cleaning agent, a rinse cleaningagent, a vapor cleaning agent, a gap cleaning agent, and an agent forwater draining and cleaning.

Additionally, specific utilities thereof include for example varioustest solvents such as solvent for switch withstand voltage, solvent forceramic depolarization test, solvent for Braun tube socket withstandvoltage, and solvent for film condenser withstand voltage; liquid mediumfor rectifier; liquid medium for transformer; liquid medium forcondenser; cooling and heating liquid medium for cooling semiconductorproduction apparatuses and dry etching apparatuses, ozone apparatus,liquid crystal projector, and power source heat exchanger; solvent forproducing fluorine polymers; solvent for forming film from fluorinatedsilicon polymer; cleaning agent of hollow fiber; dry cleaning solvent;solvent for fluorine-containing electrolytes; optical disk, magneticdisk; solvent for forming surface lubricating layer on magnetic disk andmagnetic tape; solvent for checking crack or leakage in castings andceramic products; solvent for chemical reactions including reaction withLewis acid catalysts and the like; hollow cleaning solvent; diskpolishing solvent for silicon wafer substrate, metal substrate and glasssubstrate; cleaning agent for the production of semiconductor IC chip;surface treating solvent of printed circuit board; solvent for chemicalmechanical polishing; solvent for photoresist; solvent for developingsolution; and rinse solution composition. The inventive fluorinatedhydrocarbon can be used as a medical medium, such as aerosol medium forhumans, including dosage forms such as external dosage forms ofanti-inflammatory agents, therapeutic agents of muscle fatigue, topicalheating agents, analgesic agents, blood circulation promoting agents,coating and spreading dosage forms on human skin, inhalation agents,intra-nasal droplets, anti-odor agents, sterilizers, and cleaning andwiping agents; sterilization and cleaning agents of hollow fiber fordialysis; cooling medium for medical cooling apparatuses forcryoperation and medical treatment of head, by means of catheters;polymer-containing solution for forming polymer film on the surface ofdisposable products such as catheter, implants, guide wire, circuit andsensor and of implants such as artificial blood tube, stent, andartificial bone; cleaning agent for disposable products such ascatheter, insertion device, guide wire, injection needle, circuit, bagand sensor, implants such as artificial blood tube, stent, artificialbone and dental materials, and rigid devices such as tongs, scissors,tweezers, and thoracotomy device; pressurized medium for administering atrace amount of drug in a sustained manner to a lesion; solvent forproducing gelatin capsule carrying drug; solvent for lubricantapplication during medical catheter production and solvent for lubricantremoval; and solvent for lubricant application on artificial organs andartificial blood tube and solvent for lubricant removal from theseorgans.

By dissolving or dispersing a polymer with film forming potency in aliquid medium principally containing trihydrofluorocarbon, and coatingthe resulting polymer-containing solution of the invention of theapplication on solid surface thereby forming a polymer film, theresulting polymer film is of a film thickness at a very high uniformity.

In accordance with the invention of the application, the essentialcharacteristic properties of the polymer, such as lubricationproperties, non-coherent properties and liquid repellency, can beimproved more.

Thus, the polymer-containing solution of the invention of theapplication is useful for the formation of a water repellent film oninkjet record head and is also useful for the formation of a polymerfilm with lubrication properties and non-coherent properties on cleaningblade of inkjet record head and office machines, for example rubbercleaning blade for removing residual toner on the photosensitivematerial of an electrophotographic copy machine, and the sliding partsof camera, office machine, medical apparatuses, precision machines,vacuum apparatuses such as vacuum pump, electronic parts, precisionautomobile parts, small motor, ultrasonic motor, and micro-machine andon magnetic record media such as hard disk and optical disk.

What is claimed is:
 1. A product containing 95 wt % of more of cyclictrihydrofluorocarbon with 5 carbon atoms as represented by the followingformula I: Rf₁—R₁—Rf₂  (I) wherein R₁ represents a carbon chain of CHFand CH₂, bound to each other, and Rf₁ and Rf₂ bind to each other to forma perfluoroalkylene ring.
 2. A product according to claim 1, containing99% or more of the trihydrofluorocarbon represented by the formula I. 3.A cleaning agent containing a product as the effective ingredientaccording to any one of claims 1 or
 2. 4. A method for cleaning anarticle with staining substances deposited thereon, comprising removingthe staining substances from the article by putting the article incontact with an organic solvent comprising at least one selected fromhydrocarbons, alcohols, esters, chlorinated hydrocarbons, otherfluorinated hydrocarbons, ethers, ketones, and volatile organicsilicons, and rinse cleaning such article comprising putting the organicsolvent deposited on the article after the removal of the stainingsubstances in contact with a cleaning agent according to claim 3,thereby rinse cleaning the article, or comprising vapor rinsing thearticle in the vapor of the cleaning agent.
 5. A polymer-containingsolution prepared by dissolving or dispersing a polymer withfilm-forming potency in a product according to any one of claims 1 or 2.6. A polymer-containing solution according to claim 5, wherein thepolymer with film-forming potency is at least one selected fromfluoropolymers, silicon resin, phenol resin, and polyolefin resin.
 7. Amethod for forming a polymer film on the surface of a solid, comprisingcoating a polymer-containing solution according to claim 6, on thesurface of the solid and removing the liquid medium.
 8. A method forforming a polymer film on the surface of a solid, according to claim 7,wherein the solid is magnetic record medium, optical disk, cleaningblade, or inkjet record head.
 9. A polymer-containing solution accordingto claim 5, wherein the polymer with film-forming potency has at leastone property selected from lubrication properties, non-coherentproperties and liquid repellency.
 10. A method for forming a polymerfilm on the surface of a solid, comprising coating a polymer-containingsolution according to claim 9, on the surface of the solid and removingthe liquid medium.
 11. A method for forming a polymer film on thesurface of a solid, according to claim 10, wherein the solid is magneticrecord medium, optical disk, cleaning blade, or inkjet record head. 12.A polymer-containing solution according to claim 5, wherein thepolymer-containing solution contains a lubricant comprising at least oneselected from mineral oil, silicone oil, higher alcohol, higher fattyacid and salts thereof, higher fatty acid ester and fluorine-containingsilicon compound.
 13. A polymer-containing solution according to claim12, wherein the lubricant is used at an amount of 0.01 to 50 parts byweight to 100 parts by weight of the polymer.
 14. A method for forming apolymer film on the surface of a solid, comprising coating apolymer-containing solution according to claim 13, on the surface of thesolid and removing the liquid medium.
 15. A method for forming a polymerfilm on the surface of a solid, according to claim 14, wherein the solidis magnetic record medium, optical disk, cleaning blade, or inkjetrecord head.
 16. A method for forming a polymer film on the surface of asolid, comprising coating a polymer-containing solution according toclaim 12, on the surface of the solid and removing the liquid medium.17. A method for forming a polymer film on the surface of a solid,according to claim 16, wherein the solid is magnetic record medium,optical disk, cleaning blade, or inkjet record head.
 18. A method forforming a polymer film on the surface of a solid, comprising coating apolymer-containing solution according to claim 5, on the surface of thesolid and removing the liquid medium.
 19. A method for forming a polymerfilm on the surface of a solid, according to claim 12, wherein the solidis magnetic record medium, optical disk, cleaning blade, or inkjetrecord head.
 20. A method for producing a fluorinated hydrocarbon,comprising subjecting a dihydrofluorocarbon represented by the followingformula II to an alkali treatment and subsequently hydrogenating theresulting product: Rf₁—CHF—CHF—Rf₂  (II) wherein Rf₁ and Rf₂independently represent a perfluoroalkyl group and Rf₁ and Rf₂ may bebound to each other, to form a ring.
 21. A method for producing afluorinated hydrocarbon according to claim 20, wherein thedihydrofluorocarbon represented by the formula II is an alicycliccompound.
 22. A method for producing a fluorinated hydrocarbon accordingto claim 20, wherein the alkali for the alkali treatment of thedihydrofluorocarbon represented by the formula II is at least oneselected from metal hydrogen carbonate salts, metal carbonate salts,hydroxides and anion exchange resins and the amount thereof to be usedis an equivalent or more to 1 mole of the dihydrofluorocarbon.
 23. Amethod for producing a fluorinated hydrocarbon according to claim 20,wherein the pressure for the hydrogenation reaction subsequent to thealkali treatment is atmospheric pressure to 10 kgf/cm² and the reactiontemperature is ambient temperature to about 350° C.
 24. A fluorinatedhydrocarbon composition containing a product according to any one ofclaims 1 or 2 and at least one organic solvent at a boiling point of 25°C. or more to 250° C. or less.
 25. A fluorinated hydrocarbon compositionaccording to claim 24, wherein the organic solvent is added at an amountof 50% by weight or less to the total weight.
 26. A fluorinatedhydrocarbon composition according to claim 25, wherein the organicsolvent is added at an amount of 2 to 30% by weight to the total weight.27. A cleaning agent containing a fluorinated hydrocarbon composition asthe effective ingredient according to claim
 26. 28. A polymer-containingsolution prepared by dissolving or dispersing a polymer withfilm-forming potency in a fluorinated hydrocarbon composition accordingto claim
 26. 29. A cleaning agent containing a fluorinated hydrocarboncomposition as the effective ingredient according to claim
 25. 30. Apolymer-containing solution prepared by dissolving or dispersing apolymer with film-forming potency in a fluorinated hydrocarboncomposition according to claim
 25. 31. A fluorinated hydrocarboncomposition according to claim 24, wherein the organic solvent is atleast one selected from hydrocarbons, alcohols, esters, chlorinatedhydrocarbons, other fluorinated hydrocarbons, ethers, ketones, andvolatile organic silicons.
 32. A cleaning agent containing a fluorinatedhydrocarbon composition as the effective ingredient according to claim31.
 33. A polymer-containing solution prepared by dissolving ordispersing a polymer with film-forming potency in a fluorinatedhydrocarbon composition according to claim
 31. 34. A fluorinatedhydrocarbon composition according to claim 24, wherein the compositionis an azeotropic composition.
 35. A fluorinated hydrocarbon compositionaccording to claim 34, wherein organic solvents forming the azeotropiccomposition are lower alcohols, hydrocarbons, chlorinated hydrocarbon,and other fluorinated hydrocarbons.
 36. A cleaning agent containing afluorinated hydrocarbon composition as the effective ingredientaccording to claim
 35. 37. A polymer-containing solution prepared bydissolving or dispersing a polymer with film-forming potency in afluorinated hydrocarbon composition according to claim
 35. 38. Acleaning agent containing a fluorinated hydrocarbon composition as theeffective ingredient according to claim
 34. 39. A polymer-containingsolution prepared by dissolving or dispersing a polymer withfilm-forming potency in a fluorinated hydrocarbon composition accordingto claim
 34. 40. A cleaning agent containing a fluorinated hydrocarboncomposition as the effective ingredient according to claim
 24. 41. Amethod for cleaning an article with staining substances depositedthereon, comprising removing the staining substances from the article byputting the article in contact with an organic solvent comprising atleast one selected from hydrocarbons, alcohols, esters, chlorinatedhydrocarbons, other fluorinated hydrocarbons, ethers, ketones, andvolatile organic silicons, and rinse cleaning such article comprisingputting the organic solvent deposited on the article after the removalof the staining substances in contact with a cleaning agent according toclaim 40, thereby rinse cleaning the article, or comprising vaporrinsing the article in the vapor of the cleaning agent.
 42. Apolymer-containing solution prepared by dissolving or dispersing apolymer with film-forming potency in a fluorinated hydrocarboncomposition according to claim
 24. 43. A polymer-containing solutionaccording to claim 42, wherein the polymer with film-forming potency isat least one selected from fluoropolymers, silicon resin, phenol resin,and polyolefin resin.
 44. A polymer-containing solution according toclaim 42, wherein the polymer with film-forming potency has at least oneproperty selected from lubrication properties, non-coherent propertiesand liquid repellency.
 45. A polymer-containing solution according toclaim 42, wherein the polymer-containing solution contains a lubricantcomprising at least one selected from mineral oil, silicone oil, higheralcohol, higher fatty acid and salts thereof, higher fatty acid esterand fluorine-containing silicon compound.
 46. A polymer-containingsolution according to claim 45, wherein the lubricant is used at anamount of 0.01 to 50 parts by weight to 100 parts by weight of thepolymer.
 47. A method for forming a polymer film on the surface of asolid, comprising coating a polymer-containing solution according toclaim 43, on the surface of the solid and removing the liquid medium.48. A method for forming a polymer film on the surface of a solid,according to claim 47, wherein the solid is magnetic record medium,optical disk, cleaning blade, or inkjet record head.